Modification of Pd and Mn on the Surface of TiO₂ with Enhanced Photocatalytic Activity for Photoreduction of CO₂ into CH₄

The novel Pd- and Mn-comodified TiO₂ photocatalyst (TiO₂–Pd–Mn) was prepared via a simple sol–gel method. The introduced Pd and Mn existed as the −O–Pd–O– and −O–Mn–O– species on the surface of the photocatalyst. The band structure and density of states are studied by theoretical calculations, which is demonstrated by the experimental results. The modification with Pd and Mn ions results in the strong visible response and efficient separation of photogenerated carriers. Thus, the TiO₂–Pd–Mn exhibit improved photocatalytic activity compared with pure TiO₂, TiO₂–Pd, and TiO₂–Mn for photoreduction of CO₂ and H₂O into CH₄. It is an effective method on developing the highly active TiO₂-based materials by modification with double elements on the surface